Commercial acceptance of heretofore known printing plates having a polymeric printing layer has been impeded for reasons such as unsatisfactory adherence of the polymer layer to various substrates. Good adherence of the polymer layer to the substrate is especially important in large volume printing applications such as those encountered in the newspaper industry.
Also, the substrates prepared according to the teaching of U.S. Pat. Nos. 3,748,190 and 3,826,651 do not give satisfactory adhesion to ultraviolet cured, ethylenically unsaturated polyetherurethanes such as those described in U.S. Pat. No. 4,139,436, which are to be used for exceptionally long printing runs or where better half tone quality is desired.